Sewing machine work supports



oct. s, 1957 F. PARRY Erm.

SEWING MACHINE woRx SUPPORTS 3 Sheets-Sheet 1 Filed Oct. 22,. v1954 INVENTORS. Frank Parry and Earl F'. Dunn WITNESS mavgcj,

AT TORNE Y Oct. 8, 1957 F. PARRY ETAL SEWING MACHINE woRK SUPPORTS Filed OCT.. 22,- 1954 3 Sheets-Sheet 2 INVENTORS.

Frank Parry and BY `Earl F. Dunn l nWWQTTQRNEY wmvEss MXLQ Oct. 8, 1957 F. PARRY l-:TAL

SEWING MACHI'NE WORK SUPPORTS 3 Sheets-Sheet 3 Filed Oct. 22. 1954 INVENToRsl' Earl F. Dunn W Frank Parry and Fig. 5.

ATTORNEI w/T/vEss 8 SEWING MACHINE WORK SUPPORTS Frank Parry, Trumbull, and Earl F. Dunn, Devon, Conn., assignors to The Singer Manufacturing Company, Eiizabeth, N. J., a corporation of New Jersey Application ctober 22, 1954, Serial No. 463,862

Claims. (Cl. 112-260) This invention relates to manually operable mechanism which is adapted to separate the opposed workmanipulating instrumentalities of a sewing machine for removal and introduction of fabrics therebetween.

The present invention may be applied to any sewing machine which includes a work-feeding mechanism of the type wel known in the art in which the work fabric is compressed between two opposed surfaces of the sewing 'machine of which at least one surface is periodically shifted to carry the work with it past the stitch-forming instrumentalities. Our invention, however, is particularly advantageous and is illustrated in its preferred form in the accompanying drawings as applied to a blindstitch sewing machine of the type which is disclosed in detail in the U. S. patent of Dearborn, No. 1,592,446, July 13, 1926. In this type of blindstitch sewing machine, the stitch-forming instrumentalities operate above a workengaging plate that is fixed on the sewing head of the machine, and the work feed dog depends and operates through suitable openings in this xed plate. The work fabrics are urged upwardly against the fixed work-engaging plate and against the feed dog by means of one or more presser feet which are spring biased upwardly from a work-supporting arm. The work-supporting arm carries a movable ridge-forming member which elevates the work fabric into the path of the needle of the stitch-forming instrumentalities and in order to resist the action of the ridge-forming member, the work-supporting arm is, in turn, spring biased upwardly.

The present invention is concerned with manually operated mechanism for shifting the presser feet and the work-supporting arm away from the feed dog and the work-engaging plate so that the work fabrics will be released. It is an object of this invention to provide a mechanism for separating these components of the workmanipulating mechanism of a sewing machine by the use of a force which amounts to only a small fraction of that which is normally available to bias the parts into work-engaging relation.

It is further object to provide an arrangement of a plurality of spring means capable of biasing the components of the work-manipulating mechanism intoworkengaging relatiomand a novel mechanism for rendering certain of the spring means ineective as the components are manually separated.

It is also an object of this invention to provide a mechanism of the above character in which the plurality of spring means for biasing the work-manipulating cornponents into work-engaging relation will be locked into operative relation whenA the parts are returned to their work-engaging positions.

With the above and other objects and advantages in view as will hereinafter appear, this invention comprises the devices, arrangements, and combinations of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment thereof in which:

Figul represents a vertical sectional view taken subatent C 2 stantially transversely of a blindstitch sewing machine having our invention applied thereto.

Fig. 2 is a top plan view of a portion of the sewing machine of Fig. 1 with portions of the work table being broken away better to illustrate the work table locking mechanism of our invention. l

Fig. 3 represents a sectional view of the sewing machine taken substantially along line 3 3 of Fig. 2.

Fig. 4 represents a fragmentary Vertical sectional view of the sewing machine taken substantially as in Fig.V l and illustrating a modified form of our invention.

Fig. 5 represents a fragmentary sectional view of the sewing machine taken substantially along line 5 5 of Fig. 4. l

Referring to the drawings, the sewing machine to which this invention has been applied comprises a frame including a base portion .10 from which rises a standard 11 supporting a forwardly extending sewing head 12. Fixed with respect to the machine frame in the sewing head is a work-engaging plate 13 above which a curved needle 14 and a looper 15 are arranged to operate. The plate 13 is apertured to accommodate a work feed dog, a portion of which appears at 16 in Fig. 1, which is supported in the sewing head and depends through the work-engaging plate. The stitch-forming instrumentalities and the work-feeding mechanism are actuated from a main shaft 17 by suitable mechanism (not shown) in the sewing head.

Supported at the front of the machine bed portion 10 and extending across the front of the machine to a position beneath the work-engaging plate 13 is a work-supporting arm 18. A presser member 19 is shiftably supported with respect to the arm 18 and is spring biased upwardly in a manner well known in the art. v The work-` supporting arm also carries a ridge-forming mechanism which is indicated generally as 20 in Fig. 1.

The mechanisms of the blindstitch sewing machine, thus far described do not form a part of the present invention and, therefore, the specific details of construction of these mechanisms are not shown in the accompanying drawings. follows the disclosure of the previously referenced Dearborn Patent No. 1,592,446, while the specific details of construction of these mechanisms are more clearly shownl in the prior U. S. patent of Parry, No. 2,678,619, May 18, 1954, to which reference may be had for a more complete disclosure thereof.

The subject of this invention relates to the construction and arrangement of the mount for the work-supporting arm 18, to the arrangement of means for urging the work-supporting arm into operative position, and to the means for depressing the arm without requiring the exertion of a force suicient to oppose the accumulated pressure of all of these biasing means. The details of these constructions and arrangements willv now be described.-

A bracket member 21, which is secured to the front wall of the frame base portion 10 by fastening screws 22, is designed to carry not only the work-supporting varm 18, but also parts of the mechanism for biasing the worksupporting arm upwardly as well as parts of the mechanism for depressing the work-supporting arm for insertion and removal ofthe work. To this end, the bracket member 21 is formed with outwardly extending-anges 23 and 24 disposed one at each side. Extending between the anges and xed in each flange by means of a set screw 25 is a cylindrical bar v26 formed in its ends with a conical depression 27, these depressions being aligned axially of the cylindrical bar. and adapted to serve as pivotal on bearing` points for the work-supporting arm 18. As is Yshown in Figs. 2 and A3, the left hand or free extremity 28 of the work-supporting arm 18 is narrowed The general arrangement of the machinel as it extends to a point beneath the sewing head. The right hand extremity of the work-supporting arm is formed with depending walls including a rear wall 29, a front wall 30, an end wall 31 and a sidewall 32 which, as shown in Fig. 2, extendsv between the front wal1,3ll and the narrowed free extremity 28. The end wall 31 and thesidewall 32 are formed with aligned bores to accommodate pintles 33 and 34, respectively, which pintles are adapted to enter the conical depressions 27 at each end of the cylindrical bar 26 and thus pivotally to support the work-supporting arm with respect to the machine frame. The piutle 33 is preferably shouldered as is shown in the drawings and may be locked in place in the sidewall 32 by means of a set screw 35. The pintle 34 is similarly provided with a set screw 36 by which it may be locked in place in the endwall 31, but it is preferably formed with a threaded extremity 37 by which a iine axial adjustment of the pintles may be had with respect to the cylindrical bar upon which they are pivoted.

As shown in Fig. 3, there is freely journaled on the cylindrical bar 26 a spring carrier block 38 and a stopblock 39, these blocks being maintained adjacent one to the other and in selected axial position along the bar 26 between the flange 24 of bracket member 21 and a collar 4U which is xed to the bar 26. As best illustrated in Fig. l, the spring carrier block 38 is biased in a counterclockwise direction by a coil spring 42 whichV is Afast on an adjusting hook 43 secured in the frame base portion 10. A relatively heavy leaf spring 44 is secured to the spring carrier block by means of a fastening screw 45, and the spring 44 extends beneath the work-supporting arm 18 and against an adjusting stop screw 46 threaded therein. The leaf spring 44 is rendered captive within the work-supporting arm by an adjustable stop screw 47 which is threaded into the front wall 30 of the worksupporting arm and adapted to bear against the spring carrier block. The spring 44 is termed captive since it is conned between the stop screws 46 and 47 of which both are threaded into the work-supporting arm. The stop block 39 which is journaled on the bar 26, has formed integral with it a lever-arm 48 which extends within the machine base portion and is formed at a point beneath the standard with a slot 49 which is adapted to accommodate a roller 50 carried by a rod 51 which is slidably journaled in a bearing 52 projecting from the machine frame. The rod 51 is formed slidably to embrace a restraining pin 53 which is threaded into the bearing 52 and which serves to restrain the rod 51 from rotation and to permit endwise sliding movement thereof. The vertical position of the rod 51, and hence by virtue of the roller 50 and the slot 49, the angular position of the stop block 39 and thus the operative position of the Worksupporting arm 18 may be adjusted. Such adjustment is accomplished by means of a manual adjusting knob 54 which is journaled freely in the machine standard and which is threaded internally so as to accommodate a threaded upper extremity of the rod 51 after the fashion of a turnbuckle. The knob 54 is preferably formed loosely to straddle a retaining screw 55 which is threaded into the machine standard to prevent vertical movements of the knob. Y Y Y The above described mechanism for adjusting the operative position of the work-supporting arm forms the subject of a copending application of Frank Parry, Serial No. 463,089, filed Octoberl9, 1954.

The stop block 39 is formed in its front face with a shallow recess 56 which loosely accommodates a tang 57 which extends laterally from the spring carrier block 38. By this construction, the normal position of the spring carrier block 38, and with it the work-supporting arm 18 with the captive spring 44, in response to the biasing effect of the coil spring 42, is limited and determined by the stop block 39 and hence by the adjusting knob 54. The purpose of the construction thus far described is to pro- Y 4 vide a convenient adjustment for the height of the ridgeformer mechanism 20 in the work-supporting arm with respect to the work-engaging plate tixed in the sewing head.

The stop block 39 and the spring carrier block 38 are further locked together by a pin 58 which is slidable in a bore 59 formed transversely of the stop block 39. The pin 58 is adapted to project into a substantially vertical slot 60 formed in the contiguous face of the spring carrier block 38. The pin 58 is biased into the slot 60 by means of a spring 61 which is disposed within the bore 59 and is coniined by means of the threaded bushing 62 at one end of the bore 59. In the normal position of the locking pin 58, therefore, the blocks 38 and 39 are secured together and the spring 44 becomes anchored to the machine frame by way of the stop block 39 and the lever arm 48. In this arrangement of parts, depression cf the work-supporting arm will be resisted by the coil spring 42 and by the heavy leaf spring 44. This represents the position of parts which is desirable, for instance, during machine operation when a heavy thickness of work as in the case of a seam, etc., will be resisted by the heavy leaf spring 44 so that the ridge-former mechanism 20 will operate successfully on a wide range of fabric thicknesses and types.

As shown in Figs. 2 and 3, a mechanism is provided whereby the Work-supporting arm may be manually depressed at the will of the machine operator to remove or introduce fabrics to the stitching point. To this end, a knee-shifter device has been provided comprising a bracket 63 which may be secured to the base portion of the sewing machine frame. The bracket is formed with spaced arms 64 and 65 which are bored to provide bearings for a rod 66 bent downwardly at a point in front of the sewing machine and tted with a knee press 67. Fixed to turn with the rod 66 between the spaced bracket arms 64 and 65 is a rock arm 68 which is operatively connected to the end wall 31 of the work-supporting arm by means of the links 69 and 70, the link 70 being secured to the work-supporting arm 18Y by a fastening screw 71. Disposed between the rock arm 68 and the bracket arm 64 is a torsion spring 72 which is disposed to urge the knee-shifter device into an inoperative position.

Also fast upon the rod 66 is a second rock arm 73 which is formed at its free extremity to receive a replaceable wear resistant insert 74. The insert may be of any desired material, however, nylon has been found to be highly satisfactory. The insert is secured to the rock arm 73 by means of a pin 75, a fastening screw 76 and a lip 77 which extends from the rock arm over the insert 74. The wear resistant insert 74 is adapted to bear against the cam-like extremity 78 of the slide bar 79 which is confined to move along a slot 80 formed inthe bracket 21 by means of spaced keeper members 81 and 82. The slide bar 79 is formed with an outwardly and downwardly bent portion formed with a bifurcated extremity 83 which is disposed to embrace the locking pin 58 between spaced stop nuts 84 and 85. The slide bar 79 is formed with a separable scarf joint 86 approximately midway of its length to facilitate assembly at which joint the parts are fastened together by screws 87 and 88. The cam-like extremity 78 of the slide bar 79 is formed with a straight substantially vertical portion 89 against which the wear resistant insert 74 bears upon initial movement of the knee press. The slide bar 79 is shifted along the slot 8l) during the travel of the insert 74talong this straight portion 89 so that the locking pin 58 will be shifted out of the slot 60 in the spring carrier block 38. Thus, with the initial movement of the knee press the spring carrier block 38 will be unlocked from the stop block 39 and the heavy leaf spring 44 will become free of the machine frame. Continued movement of the knee press will shift the wear resistant insert 74 to a curved portion 90 of the cam like extremity of the push rod. The center of curvature of this curved portion 90 s chosen to coincide with the axis of the rod 66 of the knee shifter device so that no further movement of the slide bar 79 will occur after the initial unlocking movement. The links 69 and 70 which connect the knee shifter rock arm 68 with the work-supporting arm 1S, are preferably provided with sufficient lost motion so that the above described unlocking movements of the slide bar 79 and the locking pin 58 can occur before the links 69 and 70 become taut. Then during continued motion of the knee shifter, the work-supporting arm will be depressed by the direct mechanical connection provided by the links 69 and 70. Since the leaf spring 44 is not anchored to the machine frame, the work-supporting arm is depressed in opposition to only the relatively light coil spring 42 which is well within the physical capacity of a machine operator to overcome. The leaf spring 44 during this time will remain captive between the stop screws 46 and 47 in the arm 18.

When the knee press is released, the reverse sequence occurs, namely, the combined effect of the light coil spring 42 upon the work-supporting arm 18 and the torsion spring 72 of the knee press will return the work table and the knee press to normal positions and the arm 18 will thus be elevated into the position shown in the drawings. During the tinal return movement of the knee press, the wear resistance insert 74 will again track the straight portion 89 of the slide bar extremity which will permit the spring 61 to bais the locking pin 58 into the slot 60 in the spring carrier block 38 whereupon the leaf spring will again be anchored to the machine frame so as to resist any efforts toward depression of the worksupporting arm.

Fig. 4 and 5 illustrate an alternative form of construction of our invention which differs from that illustrated in Figs. l, 2 and 3 only in the form and disposition of the captive spring. As is shown in Fig. 4, a coil spring 91 is disposed on a stud bolt 92 which passes through a clearance aperture 93 in the front skirt 30 of the work table. The coil spring 91 is maintained captive in compression on the stud bolt by means of an enlarged head portion 94 formed on the bolt and a lock nut 95 which is threaded on the free extremity of the bolt which protrudes through the clearance aperture 93. interposed between the coil spring 91 and the front skirt 3i) of the work table is a dished arm 96 formed to extend from the spring carrier block 38. The dished arm 96, as best illustrated in Fig. 4, is preferably formed with a downwardly open bolt accommodating slot 97 to facilitate assembly of the parts.

The captive coil spring 91 of the modified form cooperates with the work table lowering mechanism to produce the same end result as does the captive leaf spring 44. The captive spring 91, like spring 44, is maintained continuously in stressed relation with respect to the work table, and by means of the dished arm 96, the spring carrier block 38 is urged by the captive spring to a position against the front skirt 39 of the work table. Since the remainder of the work table lowering mechanism has not been modified in the version illustrated in Figs. 4 and 5, it operates as described hereinbefore, first to unlock the spring carrier block 38 from the stop block 39, thus releasing any connection between the captive spring 9i and the machine frame, and then to turn the work table about its pintle bearings 34 into lowered position in opposition only to the light coil spring 42.

Having thus set forth the nature of the invention, what we claim herein is:

l. In a blindstitch sewing machine having a frame, stitch-forming mechanism carried by said frame, and a work supporting arm shiftably supported on said frame and having an operative position adapted to maintain work fabrics within the zone of action of said stitchforming instrurnentalities, means effective to urge said work-supporting arm toward said operative positionrcom- 6 prising rst and second spring means, a spring carrier block movably supported by said frame, said iirst spring means being arranged between said work-supporting arm and said spring carrier block, said second spring means being arranged between said spring carrier block and said frame, and means under control of the sewing machine operator for selectively locking said spring carrier block with respect to said frame to render said first spring means effective or for freeing said spring carrier block for movement with respect to said frame to render said second spring means effective.

2. ln a blindstitch sewing machine having a frame, stitch-forming mechanism carried by said frame, and a work-supporting arm carried on said frame for movement into and out of an operative position adapted to maintain work fabrics within the zone of action of said stitchforming mechanism, spaced abutments carried by said work-supporting arm, a spring means maintained captive between said abutments, a carrier block associated with said spring means and disposed between said spring means and one of said spaced abutments for movement relative to said abutments, and means under control of the sewing machine operator for locking said carrier block to said frame when said work-supporting arm is in operative position.

3. ln a blindstitch sewing machine having a frame, stitch-forming mechanism carried by said frame, and a work-supporting arm pivotally supported on said frame for movement into and out of an operative position adapted to maintain work fabrics within the zone of action of said stitch-forming mechanism, spaced abutments carried by said work-supporting arm, a spring means maintained captive in stressed relation between said abutments, a spring carrier block pivotally supported on said frame coaxially of said work-supporting arm, said carrier block being disposed to extend between said spring means and one of said abutments, and means under control of the sewing machine operator for locking said carrier block immovably with respect to said frame. t

4. in a blindstitch sewing machine having a frame, stitch-forming mechanism carried by said frame, and a work-supporting arm carried on said frame for movement into and out of an operative position adapted to maintain work fabrics within the zone of action of said stitch-forming mechanism, spaced abutments carried by said work-supporting arm, a first spring means maintained captive between said abutments, a movable car- Iier block associated with said irst spring means and disposed between said spring means and one of said spaced abutments, a second spring means disposed to act between said carrier block and said frame, means effective during operation of said sewing machine for locking said carrier-block to said sewing machine frame so as to arrange said first spring means between said work-supporting arm and said frame, means for manually shifting said work-supporting arm out of operative position, and means under control of said last mentioned means for unlocking said carrier block from said frame.

5. In a blindstitch sewing machine having a frame, stitch-forming mechanism carried by said frame, and a work-supporting arm carried on said frame for movement into and ont of an operative position adapted to maintain work fabrics within the zone of action of said stitchforming mechanism, means for biasing said work-supporting arm toward said operative position comprising, spaced abutments carried by said work-supporting arm, spring means held captive between said abutments, a spring carrier block disposed to extend between said spring means and said spaced abutments, `a stop block carried by said frame and disposed to engage and limit the position of said work-supporting arm, and means in the form of a pin slidably disposed in said stop-block and shiftable into and out of engagement with said spring carrier block, means under control of the machine operator for shifting said work-supporting arm into inoperative position, and means rendered effective by initiationof said last mentioned means for shifting said locking pin out of engagement with said spring carrier block. 6. In a'blindstitch sewing machine having a frame, stitch-forming mechanism carried by said frame, and a work-supporting arm carried on said frame for movement into and out of an operative position adapted to maintain work fabrics within the zone of action of said stitch-forming mechanism, means for biasing said worksupporting arm toward said operative position comprising, spaced abutments carried by said work-supporting arm, spring means held captive between said abutments, a spring carrier block disposed to extend between said spring means and said spaced abutments, a stop block carried by said frame and disposed to engage and limit the position of said work-supporting arm, and means in the form of a pin slidably disposed in said stop-block and shiftable'into and out of engagement with said spring carrier block, mechanism for shifting said work-supporting arm to an inoperative position comprising, a shaft journaled in bearings which are fixed with respect to said machine frame, manually operable means for turning said shaft, operative connections between said shaft and said work-supporting arm effective to shift said arm into inoperative position when said shaft is turned, and means for rendering said biasing spring means ineffective comprising, cam means carried by said shaft, a cam follower xed for movement with said locking pin and disposed for actuation by said cam means to shift said pin out of engagement with said spring carrier block when said shaft is turned.

7. A blindstitch sewing machine comprising a frame, a work-supporting arm, means deiining a pivotal axis for said work-supporting arm with respect to said frame, a member pivoted to said frame on an axis coincident with the pivotal axis of said work-supporting arm, an abutment means associated with said work-supporting arm and arranged for engagement with said member to limit pivotal movement thereof in one direction with respect to said work-supporting arm, spring means disposed in captive stressed relation between said worksupporting arm and said member urging said member into Vengagement with said abutment means, and operator controlled mechanism edective to lock said member against rotation with respect to said frame.

'8. AV blindstitch sewing machine comprising a frame, a work-supporting arm, means deiining a pivotal axis for said work-supporting arm with respect to said frame, a spring carrier member pivoted to said frame on an axis coincident withthe pivotal axis of said worksupporting arm, an `abutment means associated with said wcirlpsiip porting 'arm and arranged for engagement with said spring carrier member to limit pivotal movements thereof in one 'direction with respect to said work-supporting arm,

a leaf spring captive between said work-supporting armY and said spring carrier member, said leaf spring being disposed in a stressed condition between said parts and being arranged to bias said spring carrier member into engagement with said abutment means, and operator influenced means effective to prevent turning of said spring carrier member with respect to said frame.

9. A blindstitch sewing machine comprising a frame, a Work-supporting arm, means dening a pivotal axis for turning movement of said work-supporting arm with respect to said frame, a spring carrier member pivoted to said frame on an axis coincident with the pivotal axis ot said work-supporting arm, a stud extending from said work-supporting arm, a coil spring disposed on said stud, means on said stud maintaining said coil spring captive thereon in compressed condition, a portion of said spring carrier member being disposed to extend between said coil spring and said work-supporting arm so as to be biased toward said arm, and operator influenced means eiective to prevent turning of said spring carrier member with respect to said frame.

10. A blindstitch sewing machine comprising a frame,

a work-supporting arm having a substantially at horiV zontally disposed top portion and a vertically depending front skirt, means pivoting said work-supporting arm with respect to said frame on an axis disposed adjacent the juncture of said top portion with said front skirt, a block pivoted at its upper extremity to said frame on an mis substantially coincident with the pivotal axis of said work-supporting arm,` said block being formed beneath said pivotal axis with an aperture, a bolt extending from said front skirt and through said aperture, a coil spring, means on said bolt maintaining said coil spring thereon and in compression against the side of said block opposite said front skirt, and operator influenced means eifective to prevent turning of said spring carrier member with respect to said frame.

References Cited in the lile of this patent UNiTED STATES PATENTS 2,106,080 Bowman Jan. 18, 1938 2,158,246 Moulton et al May 16, 1939 

